Less than a week after the official launch of Steam Greenlight, Valve announced Tuesday that it will require a $100 fee for new submissions to the service, due to a large amount of illegitimate submissions.

As Alden Kroll of Valve wrote in the blog post, "unfortunately a significant amount of noise and clutter being submitted, either as a joke or by fans not fully understanding the purpose of Greenlight." Valve had its work cut out for it over the holiday weekend banning the large influx of illegitimate submissions, including entries for a purported 9/11 simulator, Half-Life 3, porn games and more.

The $100 fee will be required for all new Steam Greenlight submissions, and the proceeds will be donated to Child's Play, in the spirit of Valve's original intention of not making money from the Greenlight program. However, the amount of spam is making it hard for users to find real legitimate games that could use the exposure granted by Greenlight, hence the change.

The blog post notes that "[a]nyone who has already posted a submission to Greenlight will not have to retroactively pay for any existing submissions, but will need to do so for any future submissions."